PHP进阶与redis锁限制并发访问功能示例

全栈程序员-站长 • 2021年10月27日下午7:00 • 未分类 • 阅读 41

<?php
/**
 * Redis锁操作类
 * Date:  2017-06-30
 * Author: fdipzone
 * Ver:  1.0
 *
 * Func:
 * public lock  获取锁
 * public unlock 释放锁
 * private connect 连接
 */
class RedisLock { // class start

  private $_config;
  private $_redis;

  /**
   * 初始化
   * @param Array $config redis连接设定
   */
  public function __construct($config=array()){
    $this->_config = $config;
    $this->_redis = $this->connect();
  }

  /**
   * 获取锁
   * @param String $key  锁标识
   * @param Int   $expire 锁过期时间
   * @return Boolean
   */
  public function lock($key, $expire=5){
    $is_lock = $this->_redis->setnx($key, time()+$expire);

    // 不能获取锁
    if(!$is_lock){

      // 判断锁是否过期
      $lock_time = $this->_redis->get($key);

      // 锁已过期，删除锁，重新获取
      if(time()>$lock_time){
        $this->unlock($key);
        $is_lock = $this->_redis->setnx($key, time()+$expire);
      }
    }

    return $is_lock? true : false;
  }

  /**
   * 释放锁
   * @param String $key 锁标识
   * @return Boolean
   */
  public function unlock($key){
    return $this->_redis->del($key);
  }

  /**
   * 创建redis连接
   * @return Link
   */
  private function connect(){
    try{
      $redis = new Redis();
      $redis->connect($this->_config['host'],$this->_config['port'],$this->_config['timeout'],$this->_config['reserved'],$this->_config['retry_interval']);
      if(empty($this->_config['auth'])){
        $redis->auth($this->_config['auth']);
      }
      $redis->select($this->_config['index']);
    }catch(RedisException $e){
      throw new Exception($e->getMessage());
      return false;
    }
    return $redis;
  }

} // class end

?>

demo.php

<?php
require 'RedisLock.class.php';

$config = array(
  'host' => 'localhost',
  'port' => 6379,
  'index' => 0,
  'auth' => '',
  'timeout' => 1,
  'reserved' => NULL,
  'retry_interval' => 100,
);

// 创建redislock对象
$oRedisLock = new RedisLock($config);

// 定义锁标识
$key = 'mylock';

// 获取锁
$is_lock = $oRedisLock->lock($key, 10);

if($is_lock){
  echo 'get lock success<br>';
  echo 'do sth..<br>';
  sleep(5);
  echo 'success<br>';
  $oRedisLock->unlock($key);

// 获取锁失败
}else{
  echo 'request too frequently<br>';
}

?>